This application claims the right of priority under 35 U.S.C. xc2xa7 119 based on Japanese Patent Application Nos. JP 2002-1358, filed on May 8, 2002, and JP 2003-124208, filed on Apr. 28, 2003 which are hereby incorporated by reference herein in their entirety as if fully set forth herein.
1. Field of the Invention
This invention relates to a method of manufacturing an image forming apparatus with a multiple electron source comprising a number of electron emitters.
2. Description of the Related Art
Conventionally, as a method of suppressing variation of electron emission characteristics of individual electron emitters constituting the multiple electron source, known is a method of adjusting a characteristic disclosed in JP-A-10-228867 (Literature 1) and JP-A-2000-243256 (Literature 2).
In the literature 1, disclosed is a fact that, in a multiple electron source in which Surface Conduction Electron Emitters (hereafter, represented by SCE-emitter) are arranged in a matrix, voltage to be measured of voltage value higher than display drive voltage is applied, and emission current or light emitting luminance is measured as electron emission characteristic of each SCE-emitter, and based upon the characteristic, standard value of the electron emission characteristic is obtained, and thereafter, characteristic shift voltage further higher voltage value than the voltage to be measured is determined so that the electron emission characteristic of each SCE-emitter becomes the value corresponding to the standard value, and by applying it to each SCE-emitter, the electron emission characteristics of respective SCE-emitters are aligned uniformly.
Further, in the literature 2, disclosed is a series of characteristic adjustment processes comprising a first period in which preliminary drive voltage of higher voltage value than the display drive voltage is applied to all SCE-emitters, a second period in which the electron emission characteristics of respective SCE-emitters are measured by applying the display drive voltage thereto, a third period in which the characteristic shift voltage of higher voltage value than the preliminary drive voltage is applied to each SCE-emitter, and a fourth period in which the electron emission characteristic is measured again by applying the display drive voltage after the characteristic shift voltage was applied.
However, in the characteristic adjustment process in which the characteristic is adjusted so as to become a value corresponding to the standard value of the conventional technology as described above, it was possible that variation of adjustment situations occurs with respect to each emitter.
Also, It is possible that, due to this occurrence of the variation of adjustment situations, the characteristic shift voltage was applied excessively so that the characteristic becomes of a value less than the standard value, and the characteristic was not shifted up to the standard value even after the characteristic shift voltage was applied only for a desired time period, which means that uniformity is not sufficiently improved.
Furthermore, there was a case that, when an identical amplitude is applied with respect to each emitter, shift amount is smaller than estimated amount in advance, and the time required until the characteristic is shifted to a target value is lengthened so that the process becomes a unrealistic lengthy process.
Accordingly, it is desired to establish a characteristic adjustment process which has higher versatility so as to be able to correspond to such variation of adjustment situations, and further, shifts the characteristic to the standard value with good precision.
Also, it is desired to avoid visual unevenness when an observer watches a displayed image.
This invention was made to solve the above-described problems of the conventional technology, and has an object to provide a method of manufacturing an image forming apparatus which adjusts a characteristic of a multiple electron source in a matter of minutes, and uniforms an in-plane luminance characteristic of image display.
The present invention is a method for manufacturing an image forming apparatus having a multiple electron source in which a plurality of emitters are disposed on a substrate and fluorescent materials for emitting light by irradiation of electron beam from the multiple electron source, comprising: a first measurement step of measuring change of luminance, when a pulse having a plurality of amplitudes larger than drive voltage is applied to the predetermined number of the emitters, with respect to the amplitude of the pulse and the number of the pulse; a step of preparing, on the basis of the measurement result of the first measurement step, a look-up table for storing the amplitude of the pulse and the number of the pulse for shifting characteristic of emitters to a predetermined luminance target value; a second measurement step of measuring the luminance when the drive voltage is applied to the emitter; and step of applying, on the basis of the measurement result of the second measurement step, characteristic shift voltage comprising a plurality of pulses in which the amplitude of the pulse obtained from the: look-up table has two or more values, to the emitter.
Another aspect of the present invention is a method for manufacturing an image forming apparatus having a multiple electron source in which a plurality of emitters are disposed on a substrate and fluorescent materials for emitting light by irradiation of electron beam from the multiple electron source, comprising: a first measurement step of measuring change of luminance, when a pulse having a plurality of amplitudes larger than drive voltage is applied to the predetermined number of the emitters, to the amplitude of the pulse and the number of the pulse; a step of preparing, on the basis of the measurement result of the first measurement step, a look-up table for storing the amplitude of the pulse and the number of the pulse for shifting characteristic of emitters to a predetermined luminance target value; a second measurement step of measuring the luminance when the drive voltage is applied to the emitter; and a step of applying, on the basis of the measurement result of the second measurement step, characteristic shift voltage comprising a plurality of pulses in which pulse width of the pulse obtained from the look-up table has two or more values, to the emitter.
Another aspect of the present invention is a method for manufacturing an image forming apparatus having a multiple electron source in which a plurality of emitters are disposed on a substrate and fluorescent materials for emitting light by irradiation of electron beam from the multiple electron source, comprising: a step of measuring change of luminance with respect to each of characteristic shift voltages and preparing a luminance adjustment rate table, when a plurality of characteristic shift voltages which have different voltage values larger than drive voltage are applied to the predetermined number of the emitters; a step of measuring luminance to set luminance target value L0 and obtaining maximum luminance Lmax, when the drive voltage is applied to the emitter; a step of determining maximum adjustment shift voltage and a group of the adjustment shift voltage with smaller voltage values than the maximum adjustment shift voltage, by referring to the luminance adjustment rate table with maximum adjustment rate Dmax of luminance of Dmax=L0/Lmax, and a step of applying the adjustment shift voltage selected from the adjustment shift voltage group to the emitter.